corwin1968

This is just academic curiosity right now but in the future I might be in the market for a new production or even custom frame. I currently weigh 375 lbs and worst case scenario is that I stay at this weight. Best case scenario might have me in the mid-200's so I'll always be very heavy as far as bikes go.

I've been wondering about the differences between basic tubesets, like the cromoly 4130 used in Surly frames, and higher end tubesets used in more expensive frames. It's my understanding that a high-end steel like OX Platinum is stronger so less can be used, resulting in a lighter frame at a given durability level while a basic steel will result in a heavier frame at the same durability level. It's also my understanding that a lot of what differientiates a really high quality frame is "flex" from thinner tubing enhancing the ride in various ways.

My question is this: Given a tubeset that is strong enough for a rider my size, would the thickness of that tubeset keep that "flex" from occurring, thus negating the benefit of a high quality tubing? For a guy my size, is there really any benefit to a high level of tubing given that it's going to be quite thick anyway? Would a higher level of thick tubing flex less? Would that be a benefit to a guy my size?

busdriver1959

I Weigh 165 but I find that my OX Platinum bike is very stiff in the bottom bracket. I really can feel a difference when I'm out of the saddle compared to an older Lightspeed titanium I used to ride. However, it's still comfortable and soaks up bumps well. It comes in at 19 pounds with a mix of Campy Veloce and Chorus. The tubes are thin, 7/4.5/7 but if I don't beat it, it should last a long time. My guess is that OX Platinum would be a good choice if you drop into the mid 200s but somebody with more experience will have to advise you if you stay around 375.

unterhausen

This is a gross generalization, but I am not sure that there is any point in using anything other than straight gage 4130 for someone who weighs much over 250 or so, particularly if they are tall. There is a lot of mysticism about flex/planing that I'm not sure I buy into. Strong riders that weigh about 200lb usually are unhappy with frames that someone that weighs 150 or less finds pleasantly flexy. Similarly, the people that weigh 150 might find a stiff frame to feel dead.

One higher-end tube set that is made for larger riders is Columbus Max. You can simulate Max with some of the larger tubes from TrueTemper.

JohnDThompson 

I agree with unterhausen; you can get seamless 4130 tubing in a wide variety of diameters and wall thickness from places like Aircraft Spruce. Your builder should be able to select appropriate specs for the tubing depending on the type of riding you intend.

corwin1968

This is the way my thinking is going as well but even though I've been riding off and on since 1995, I've never really delved into the technicalities of frame geometry & materials, a subject that I now find fascinating.

For most the time I've been riding, I've been on a higher level Trek Multitrack. Other than being True Temper cro-moly, I know little about the tubing but I suspect it's pretty stout. I've never felt any flex in the frame but I generally stay seated at all times. I've come to the conclusion that the frame is a little on the small side (53.5cm and I'm 6' tall) and my only major complaint is the high trail, which I've addressed with a cheapo, skinny after-market fork. If I continue to ride on a regular basis, it will be worth it to me to get a better fitting frame with the geometry I want. I've spent more on custom swords and firearms than I would for a custom frame so I'm hoping to eventually go that route.

unterhausen

In that size range I might go with heat treated Verus in 9/6/9 in larger size tubes.

MassiveD

I agree with a lot of the points made. I'm a big dude, and I make bikes mostly with 4130. I have a long list of reasons, and I did essentially search for cases that would support my prejudice, but if you go this route, you are in good company. Somewhere I kept a list of recipes for clydes, though I am not sure I have it on this computer.

You may want to break out your analysis a little. For instance do you want a fancy bike with say 953. I'm sure if you asked someone could it, or some other specialty, be done, it would be possible. But if you are asking for options to go to plain tubing, they exist also. At the low end of custom plain/plane tubing won't save anything, though I guess it does at the high end, but I actually prefer it. Putting butts in tubing only answers a specific set of questions not all questions.

My own experience, as opposed, slightly, to my research, is that the heavy person can actually ride most lighter bikes. When I was 22 and stronger I weighed 195. When I took up serious cycling again at 45 for rehab from an injury, I was 270, riding a loaded bike with probably 80 pounds on it. I still owned some of my earlier bikes, and the one bike I bought was just a standard touring frame. I think weight imposes limits even on an otherwise fit hefty dude that compensate a lot for carrying that weight. Dead weight falling from on high may defeat a frame at higher magnitudes, but just heavy weight in the saddle is not always decisive. Meaning, if you are thinking of riding on the road, or smooth trail without a penchant for hopping off things, etc... you can get away with most sturdy looking stock bikes.